The present invention relates to apparatus for holding a work piece in a machine, and more particularly, to an expanding mandrel type chuck adapted for internally gripping a tubular core in a web handling apparatus, core cutter or in other applications.
Relatively thin sheet materials such as film, foil, paper, laminate and cloth are typically manufactured in the form of wide, long webs. These webs may measure, for example, six feet in width by one-thousand feet in length. Each web is usually wound about an elongate cylindrical supply core for transport and storage. The manufacture of consumer products from such webs, for example rolls of adhesive tape, usually involves the user of apparatus known as a slitter-rewinder. An example of this type of apparatus is manufactured by Arrow Converting Equipment, Inc., Law Drive, Fairfield, N.J. 07006.
A slitter-rewinder apparatus typically includes an upright frame with means for rotatably supporting the core of the supply roll. The core is typically a tubular piece of cardboard having a diameter of, for example, three inches or six inches. The slitter-rewinder apparatus must have a means of rapidly mounting and removing the supply core. During the slitting and rewinding operation, it is important that there be a positive, non-slip engagement between the supply core and the means for rotatably supporting the same.
There are a number of conventional ways in which the supply core may be mounted on the slitter-rewinder apparatus. Cone shaped mandrels mounted on stub shafts may be forced into opposite ends of the core. Another conventional approach for removably mounting the supply core utilizes a pair of chucks mounted in spaced apart relation on a shaft or shafts. The supply core is slid over the shaft so that the chucks are positioned within opposite ends of the core. In one version, the chucks include a central cylindrical body and spring steel fingers which are tangentially secured to the body. The ends of the fingers push against the inner surfaces of the core to rigidly hold the core in position relative to the shaft. The spring steel fingers eventually fatigue and must be bent outwardly. Furthermore, the fingers tend to scar the inside surface of the supply core.
Another chuck which is utilized in conjunction with slitter-rewinder apparatus to support the supply core is sold under the trademark MOHAWK by Blackhawk Company, 545--12th Street, Rock Island, Ill., 61201. This chuck has a segmented sleeve which may be expanded against the inner surface of the core utilizing a special tool. Right handed and left handed chucks must be utilized to support a supply core at each end. Depending upon the direction of web feed, it may be necessary to reverse the orientation of the MOHAWK expanding chuck.
Another chuck utilized with slitter-rewinder apparatus is sold under the trademark GRABBERS by Nim-Core, Inc., Nashau, N.H. This core chuck utilizes rubber elements.
Still another chuck utilized with slitter-rewinder apparatus is disclosed in U.S. Pat. No. 3,355,121 and is sold under the trademarks SONOCO and CHAMPION by Western Tool and Manufacturing Company, Inc., 1940 South Yellow Springs Street, Springfield, Ohio, 45506. That chuck includes a stub shaft having an intermediate portion of polygonal cross-sectional shape which underlies floating segments that are yielding urged radially outward into engagement with the cardboard core. The chuck sold under the SONOCO trademark has six spring-loaded steel balls for holding the expanding jaws outward. The present invention is an improvement of the expansible chuck of U.S. Pat. No. 3,355,121.